Agro-chemical transport processes at different scales are discussed and relevant opening questions areidentified by literature review to make some suggestions concerning the improvement of research methods forfield sc...Agro-chemical transport processes at different scales are discussed and relevant opening questions areidentified by literature review to make some suggestions concerning the improvement of research methods forfield scale solute transport by aid of evaluation of existing models, and examining transport behaviors of solutein vadose zones on different scales. The results indicate that present research progress and understanding onfield scale solute transport have not yet been enough to guarantee the use of our models for the management offield solute movement. Much more research work needs to be done, particularly, in aspects of high resolutionof spatial structures relevant to the hydraulic and transport properties, explicit numerical simulation of actualstructure on field scale and field measurement corroborated with model development.展开更多
Decentralized sewage treatment systems are commonly used in rural areas of China because these systems are low cost, easy maintenance and high efficiency. However, as awareness of the importance of sus- tainable devel...Decentralized sewage treatment systems are commonly used in rural areas of China because these systems are low cost, easy maintenance and high efficiency. However, as awareness of the importance of sus- tainable development has increased, questions concerning how to evaluate the sustainability of these systems has become a key point. In this study, emergy analysis is applied to evaluate the soil rapid infiltration for a decentralized rural sewage treatment plant that is located in Dongzhuangtou village, Qingdao, China. The results show that the environmental load ratio and the emergy sustainability index of the system are 0.07 and 242.88, respectively. The net economic benefit is 2.17E＋18 sej·year^-1 when converted into solar emjoule. Compared to other treatment systems, the environmental load ratio of the system is lower, and the emergy sustainability index is higher. This study reveals the reuse of treated water can produce great economic benefits in the soil rapid infiltration system. The environmental impact of the system is lower, and the sustainability is higher than that of other treatment systems. This result provides a quantitative evaluation of the sustainable development of rural sewage treatment systems in China.展开更多
Concentrated turtle aquaculture effluent poses an environmental threat to water bodies, and therefore needs to be treated prior to disposal. This study was conducted to assess the effect of multi-soil-layer（MSL） sys...Concentrated turtle aquaculture effluent poses an environmental threat to water bodies, and therefore needs to be treated prior to disposal. This study was conducted to assess the effect of multi-soil-layer（MSL） systems treating turtle aquaculture effluent with adding different amounts of sludge. Four MSL systems were constructed with dry weight ratios of sludge with 0%, 5%, 10%, and 20%（MSL 1, MSL 2, MSL 3, and MSL 4, respectively）. The turtle aquaculture effluent had an average chemical oxygen demand（COD）, ammonia nitrogen（NH4^＋-N） and total nitrogen（TN） concentration of 288.4, 213.4, and 252.0 mg/L, respectively. The COD/TN（C/N） ratio was 1.2. The results showed that the four MSL systems could effectively treat the COD, NH4^＋-N, and TN, and MSL 4 showed significantly improved NH4^＋-N removal efficiency, suggesting the potential of sludge addition to improve the turtle aquaculture effluent treatment. The average COD, TN, and NH4^＋-N removal efficiencies of MSL 4 were 70.3%, 66.5%, and 72.7%, respectively. To further interpret the contribution of microorganisms to the removal, the microbial community compositions and diversities of the four MSL systems were measured. Comparisons of the denaturing gradient gel electrophoresis（DGGE） profiles revealed that the amount of nitrifying bacteria and diversity in MSL 4 were higher than those in the other three systems. We concluded that adding 20% of sludge improved the NH4^＋-N removal and stability of the system for nitrification, due to the enrichment of the nitrifying bacteria in MSL 4.展开更多
文摘Agro-chemical transport processes at different scales are discussed and relevant opening questions areidentified by literature review to make some suggestions concerning the improvement of research methods forfield scale solute transport by aid of evaluation of existing models, and examining transport behaviors of solutein vadose zones on different scales. The results indicate that present research progress and understanding onfield scale solute transport have not yet been enough to guarantee the use of our models for the management offield solute movement. Much more research work needs to be done, particularly, in aspects of high resolutionof spatial structures relevant to the hydraulic and transport properties, explicit numerical simulation of actualstructure on field scale and field measurement corroborated with model development.
基金National Natural Science Foundation of China(41101080)the Shandong Natural Science Foundation(ZR2014DQ028 and ZR2015DM004)
文摘Decentralized sewage treatment systems are commonly used in rural areas of China because these systems are low cost, easy maintenance and high efficiency. However, as awareness of the importance of sus- tainable development has increased, questions concerning how to evaluate the sustainability of these systems has become a key point. In this study, emergy analysis is applied to evaluate the soil rapid infiltration for a decentralized rural sewage treatment plant that is located in Dongzhuangtou village, Qingdao, China. The results show that the environmental load ratio and the emergy sustainability index of the system are 0.07 and 242.88, respectively. The net economic benefit is 2.17E＋18 sej·year^-1 when converted into solar emjoule. Compared to other treatment systems, the environmental load ratio of the system is lower, and the emergy sustainability index is higher. This study reveals the reuse of treated water can produce great economic benefits in the soil rapid infiltration system. The environmental impact of the system is lower, and the sustainability is higher than that of other treatment systems. This result provides a quantitative evaluation of the sustainable development of rural sewage treatment systems in China.
基金supported by the Ministry of Environmental Protection of China(No.2010467014)the Science and Technology Key Plan of Huzhou(No.2011GN19),China
文摘Concentrated turtle aquaculture effluent poses an environmental threat to water bodies, and therefore needs to be treated prior to disposal. This study was conducted to assess the effect of multi-soil-layer（MSL） systems treating turtle aquaculture effluent with adding different amounts of sludge. Four MSL systems were constructed with dry weight ratios of sludge with 0%, 5%, 10%, and 20%（MSL 1, MSL 2, MSL 3, and MSL 4, respectively）. The turtle aquaculture effluent had an average chemical oxygen demand（COD）, ammonia nitrogen（NH4^＋-N） and total nitrogen（TN） concentration of 288.4, 213.4, and 252.0 mg/L, respectively. The COD/TN（C/N） ratio was 1.2. The results showed that the four MSL systems could effectively treat the COD, NH4^＋-N, and TN, and MSL 4 showed significantly improved NH4^＋-N removal efficiency, suggesting the potential of sludge addition to improve the turtle aquaculture effluent treatment. The average COD, TN, and NH4^＋-N removal efficiencies of MSL 4 were 70.3%, 66.5%, and 72.7%, respectively. To further interpret the contribution of microorganisms to the removal, the microbial community compositions and diversities of the four MSL systems were measured. Comparisons of the denaturing gradient gel electrophoresis（DGGE） profiles revealed that the amount of nitrifying bacteria and diversity in MSL 4 were higher than those in the other three systems. We concluded that adding 20% of sludge improved the NH4^＋-N removal and stability of the system for nitrification, due to the enrichment of the nitrifying bacteria in MSL 4.
